I am wondering what unlocks the Jack tool.

I have my base set up, but I have no parts for building vehicles. The internet says that they unlock with building the jack tool, but I cannot figure out what unlocks the jack tool.

I think it unlocked by scanning a vehicle I found somewhere near the landing spot. Look in your journal for a related quest. Maybe you have to build/find a scanner first.

I got the jack tool from scanning a vehicle at one of the sites near where my pod crashed.